It is known to provide filters for fluid systems to remove contaminants. One such device is shown in pending patent application PCT/US 12/047623.
Fuel contamination is a recurring problem associated with the use and operation of small internal combustion engines, such as those for lawnmowers, trimmers, edgers, vacuums and blowers, snow throwers, other gasoline engine powered yard and garden equipment, recreational equipment such as snowmobiles, boats and the like. Users of such equipment often store fuel for relatively long periods of time in fuel storage containers kept outdoors, in garages, and the like. The fuel storage containers are opened numerous times, and relatively small amounts of the fuel are transferred from the storage container to a relatively small fuel tank on the equipment.
Often, the fuel tank on the equipment is quite dirty, and may be covered with dirt, dust, grass clippings and other debris. Even when cleaned and opened carefully, debris from around the inlet opening or the surrounding areas can enter the fuel tank on the equipment. Particulate contamination of the fuel is not uncommon, and can occur both in the fuel tank that is on the equipment and in the fuel storage container. Contaminants in the fuel storage container can be transferred to the fuel tank on the equipment during a refueling operation. It is desirable to provide fuel as free from particle contamination as possible, to minimize the potential for damage to the engine, and to enable the engine to run as efficiently and trouble-free as possible.
An additional source of fuel contamination results from characteristics of present day fuels. Gasoline suppliers have increased the alcohol content in gasoline, which can present a problem during long term storage of the fuel either in a fuel storage container or in the fuel tanks on the equipment. The use of alcohol in fuels allows the phase separation of alcohol and water during temperature cycles. Since alcohol has the ability to absorb and retain water, the amount of which varies with ambient temperature, significant water volume can develop in fuels stored for extended periods of time. The alcohol in the fuel will absorb and retain water, then release the water during cold to hot to cold ambient temperature cycles. As a result, water can accumulate and remain in its natural state, subsequently fouling the fuel and possibly harming the combustion engine during use. Since the equipment itself may have infrequent use such that fuel remains in the fuel tank on the equipment for extended periods of time, fouling from the absorption and release of water can occur not only in fuel storage containers but in the fuel tank on the equipment itself. Water that has accumulated in the fuel storage container can be transferred to the fuel tank on the equipment during a refueling operation.
It is therefore advantageous and desirable to separate not only solid contaminants from fuels but accumulated water as well; and to do so as the fuel is delivered to an engine for combustion. While the problems described herein are of particular significance for the small gasoline engines described, the need for a filter as disclosed herein is not limited to such equipment. A larger gasoline engine can also benefit from use of the filter to be described. Further, other equipment circulating fluids that can be subjected to both particle contamination and fouling by water may benefit from use of the filter.